The open-top pair follow closely on the heels of the recently introduced 911 Turbo and Turbo S coupe, boasting a unique body that is 28mm wider than that of the widest of existing 991-generation 911 models, the Carrera 4, along with a signature bi-plane rear wing that deploys to provide additional downforce at speeds above 75mph.

A revised fabric roof, now fitted with a lightweight magnesium frame, opens and stows in a dedicated compartment behind the cabin in 13. seconds at speeds of up to 37mph.

Power comes from a newly developed turbocharged version of Porsche's 3.8-litre flat six engine developing 513bhp in the 911 Turbo cabriolet and 552bhp in the 911 Turbo S cabriolet. It has a seven-speed dual clutch automatic gearbox and all-wheel drive, with traction enhanced by an electronically controlled torque vectoring system for the rear wheels .

Official figures point to 0-62mph times of 3.5sec and 3.2sec respectively. Top speed in both models is 198mph. Fuel economy has improved by 30 percent at a claimed 23.8mpg.